What is "perennation"

n. the process of living through a number of years (as a perennial plant)

In botany, perennation is the ability of organisms, particularly plants, to survive from one germinating season to another, especially under unfavourable conditions such as drought or winter. It typically involves development of a perennating organ, which stores enough nutrients to sustain the organism during the unfavourable season, and develops into one or more new plants the following year. Common forms of perennating organs are storage organs (e.g. tubers and rhizomes), and buds. Perennation is closely related with vegetative reproduction, as the organisms commonly use the same organs for both survival and reproduction.